Absorption of minocycline hydrochloride and tetracycline hydrochloride. Effect of food, milk, and iron.

Serum concentrations of tetracycline hydrochloride and minocycline hydrochloride were compared when administered with water, milk, a meal, and 300 mg ferrous sulfate in two groups of eight volunteers. Absorption of both antibiotics was significantly decreased by administration with iron (77% inhibition with minocycline and 81% with tetracycline), milk (27% inhibition with minocycline, 65% with tetracycline), and food (13% inhibition with minocycline and 46% with tetracycline). The inhibitory effect on absorption with food and milk was significantly greater for tetracycline than for minocycline.